New Tunable CFOA-Based Positive Group Delay Cascadable Circuit

This paper presents a new current-feedback operational-amplifier (CFOA) based first-order voltage mode all-pass filter (APF). The proposed circuit can be used as a tunable time-delay circuit with relatively large time delays. The circuit enjoys low output impedance and, therefore, can be easily cascaded with similar circuits to obtain larger time delays. The functionality of the circuit was confirmed using PSPICE simulation tool and commercially available integrated circuit (AD844). The simulation results show that delay can be tuned from 10 mu s to 256 mu s.